• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.544-547
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• 2003

The purpose of this paper is to develop the straightforward design guidelines of PD/PID speed controller for Industry servo drives with plug and play concept. The controller gains are uniquely determined from the current control loop dynamics, speed loop delay, and mechanical parameters. In order to eliminate the mechanical friction uncertainties, an automatic PD/PI control mode switching algorithm Is introduced using online spectrum analysis of motor torque command. The dynamic performance of the proposed scheme assures a fast tracking response curve with minimal oscillation and settling time over the whole operating conditions. For comprehensive comparison of conventional PI control scheme, extensive test is carried out on actual servo system.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.50-57
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• 1997

A fast tool servo (FTS) for diamond turning improves machining accuracy by quickly compensating relative position errors between the cutter and the workpiece. Therefore, the FTS needs to have large band-width with good tracking performance. Serious hysteresis nonlinearity of PZT actuators used in the FTS, however, deteriorates fast tracking performance. Several types of feedforward hysteresis compensators and feedback controllers are tested to improve tracking performance. Through simulations and experiments, control structure which yields the smallest tracking error is selected. The maximum peak to peak error in tracking a sinusoidal waveform is reduced by one fifth compared to that of a regular PID controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.675-678
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• 2002

A controller was designed generally using C or assembly languages on high-speed design controller. But, in this paper, DC servo controller is designed using the cord of the block-diagram of SIMTool. By the method, we can design, realized and analyzed a control system quickly in real-time. And we expect that the various plants of a robot vehicles are controled through the outside I/O board changing the structure of the block-diagram of SIMTool into AUTOTool. In addition, our developed system helps the most suitable automatic controller design and tester with hight-speed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.11
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• pp.591-598
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• 2000

In this thesis, a digital tracking controller is proposed for multi-axis position control system. Tracking and contouring error exist when the machine tool moves along a trajectory in multi-axis system. The proposed scheme enhances the tracking and contouring performance by reducing the errors. Also, an optimal tracking controller reduces the tracking error by the state feedback and the feedforward compensator reduces the effects of a nonlinear disturbance such as friction or dead zone. The proposed control scheme reduces the contour error which occurred when the tool tracks the reference trajectory. Finally, the performance of the proposed controller is exemplified by some simulations and by applying the real XY servo system.

• Transactions of the Society of Information Storage Systems
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• v.3 no.1
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• pp.28-33
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• 2007

최근 Hard Disk Drive(HDD)는 컴퓨터 산업의 발달과 함께 멀티미디어 어플리케이션의 요구에 따라 대용량화 추세에 있다. 이러한 대용량 HDD 는 고밀도, 고정밀의 track 정보가 필요하게 되고, 이는 HDD 생산에 고속, 고정밀의 Servo Track Writer(STW)를 필요로 하게 되었다. 그러나, 기존의 STW 는 PID 제어기에 공진 모드 제거를 위한 notch filter 를 사용하기 때문에 고속화에는 한계가 있어 track 정보를 기록하는 생산시간의 단축이 어렵다. 본 논문에서는 이를 위하여 기존의 STW 에 공진 모드의 여기를 최소화하기 위해 제어 입력의 profile 을 설계하는데 convex optimization 을 이용한 최적화 기법을 사용하였다. 이렇게 설계된 제어 입력은 플랜트의 공진 모드가 존재하는 주파수 대역에 에너지를 최소화시켜 공진 모드의 영향을 적게 받는다. 그 결과로 빠른 settling time 과 위치 정밀도가 향상된다. 그 효과는 모의 실험을 통해 검증하였다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2461-2463
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• 2000

This paper presents a scheme for designing a fuzzy observer for servo control system with nonlinear element, i.e., backlash. It is found that backlash occurs when the feed direction is reversed. Due to the imperfect transient response of the driving mechanism, not only the static backlash error but also the dynamic backlash error is generated on the contouring profile. And also, we utilized two inertia modeling in order to deals with coupled system accurately. The overall control system consists of two parts - a servo controller and an Fuzzy obsever. It is a Takagi-sugeno type fuzzy model whose consequent part is of the state space form is obtained. A simulation is carried out to demonstrate the effectiveness of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.46-48
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• 1996

In almost all the servo systems, especially for the robot manipulators and numerical control systems, there are resonance effects and nonlinear frictions which should be considered in designing servo controllers. In this paper to compensate friction and track the step-input without steady-state error, the original system is augmented with an integrator and employes $\mu$-Controller design method $\mu$-Controller design method enables to meet not only performance requirements but robust stabilities simultaneously. And there may exist a limit cycles due to interaction between integrator and nonlinear friction. With describing function method, the possibility of limit cycle is checked.

• Transactions of the Society of Information Storage Systems
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• v.3 no.4
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• pp.167-172
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• 2007

The recently-developed off-line learning control approaches for the rejection of periodic disturbances utilize the specific property that the learning system tends to oscillate in steady state. Unfortunately, the prior works have not clarified how closely the learning system should approach the steady state to achieve the rejection of periodic disturbances to satisfactory level. In this paper, we address this issue extensively for the class of linear systems. We also attempt to remove the effect of other aperiodic disturbances on the rejection of the periodic disturbances effectively. In fact, the proposed learning control algorithm can provide very fast convergence performance in the presence of aperiodic disturbance. The effectiveness and practicality of our work is demonstrated through mathematical performance analysis as well as various simulation results.

• Journal of Power Electronics
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• v.10 no.6
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• pp.635-642
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• 2010

The paper presents a multimedia educational program of DC servo drives for distant learning with a special emphasis on sliding mode control. The program contains of three parts: animation, simulation and internet based measurement. The animation program explains the operation of DC motors, gives its time- and frequency-domain equations, transfer functions and the theoretical background necessary for controller design for DC servo motors. The simulation model of the DC servo motor and the controller can be designed by the students based on the animation program. The students can also test their controllers through the internet based measurement, which is the most important part from engineering point of view. After the measurements are executed, the students can download the measured data and compare them to the simulation results.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.985-986
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• 2007

Most industrial robot can not load control box on their bodies because of robot's weight and volume. A robot is connected to its control box with cables. Complicated connections cause a lot of problems on transfer, management and operating robots. To get rid of those, Control module must be made the smallest size by using advanced electronic technology. This paper represents about how to simulate servo system inserting several parameter values that we ultimately want to achieve. Through simulating, we will be able to estimate the structure of desired servo system without any mistakes that can possibly occur on hardware work.